White Blood Cells (WBC)
White blood cells act as the body’s first line of defense against foreign bodies, tissues, and other substances. WBC count assesses the total number of WBC in a cubic millimeter of blood. White blood cell differential provides specific information on white blood cell types:
- Neutrophils are the most common type of WBC and serve as the primary defense against infection.
- Lymphocytes play a big role in response to inflammation or infection.
- Monocytes are cells that respond to infection, inflammation, and foreign bodies by killing and digesting the foreign organism (phagocytosis).
- Eosinophils respond during an allergic reaction and parasitic infections.
- Basophils are involved during an allergic reaction, inflammation, and autoimmune diseases.
- Bands are immature WBCs that are first released from the bone marrow into the blood.
Normal lab values for white blood cell count and WBC differential:
- WBC Count: 4,500 to 11,000 cells/mm³
- Neutrophils: 55 – 70% or 1,800 to 7,800 cells/mm³
- Lymphocytes: 20 – 40% or 1,000 to 4,800 cells/mm³
- Monocytes: 2 – 8% or 0.0 to 800 cells/mm³
- Eosinophils: 1 – 4% or 0.0 to 450 cells/mm³
- Basophils: 0–2% or 0.0 to 200 cells/mm³
- Bands: 0–2 % or 0.0 to 700 cells/mm³
Nursing consideration for WBC count:
- A high total WBC count with a left shift means that the bone marrow will release an increased amount of neutrophils in response to inflammation or infection.
- A “shift to the right” which is usually seen in liver disease, megaloblastic and pernicious anemia, and Down syndrome, indicates that cells have more than the usual number of nuclear segments.
- A “shift to the left” indicates an increased number of immature neutrophils is found in the blood.
- A low total WBC count with a left shift means a recovery from bone marrow depression or an infection of such intensity that the demand for neutrophils in the tissue is greater than the capacity of the bone marrow to release them into the circulation.
